The authors studied the frequency distribution of alpha-actinin-3 (ACTN3) R577X genotypes in 60 top-level professional soccer players. The results were compared with those of 52 elite endurance athletes and 123 sedentary controls. The per cent distribution of RR and RX genotypes in soccer players (48.3% and 36.7%) was significantly higher and lower, respectively, than controls (28.5% and 53.7%) and endurance athletes (26.5% and 52%) (p = 0.041). Although there are notable exceptions, elite soccer players tend to have the sprint/power ACTN3 genotype.